MINNEAPOLIS / ST. PAUL--"A team of University of Minnesota scientists has discovered how iron- and chromium-rich rocks can generate natural gas (methane) and related hydrocarbons when reacted with superheated fluids circulating deep beneath the floor of the Atlantic Ocean. Because the process is completely nonbiological, the hydrocarbons could have been a source of "food" for some of the first organisms to inhabit the Earth. Also, methane is a potent greenhouse gas, and this process may have contributed to global warming early in geologic time,"